While reading an article, I had 2 SCP ideas in mind that sounds like it could work.

The first idea is a glass cup. When a liquid is poured into the cup, the effect on the drinker is much much stronger than what it should be. (e.g: Someone drinks coffee from this cup, and they suffer from insomnia.

The second idea is also a glass cup. This is kind of like above. When a liquid is poured into the cup, the effect on the drinker is different depending on what type of light passes through it (different light = color, luminesence, etc.)

1. What if someone pours vitamin water into the cup and drinks it? Air? A goldfish? "Effect is much stronger on drinker" isn't particularly specific.

2. Are you talking about light in the human visual spectrum? The butterfly's visible spectrum? The mantis shrimp's? How would anyone be able to tell it's the color of light that affects the glass? Also, ditto on the goldfish question.

I dunno. These seem like entries on the log of anomalous objects than an SCP that would merit specific Foundation containment.

To quote vezaz, "Get away from "type of object" or "sort of creature" and instead start thinking about stories you want to tell. Start looking for moments in your everyday life that give you pause, that are unusual, or that make you go off into a daydream. Then think about bringing the reader to that same moment."

Why do these things exist? What is their purpose? Is there something bigger to their story besides "thing that does a thing"?

1. What if someone pours vitamin water into the cup and drinks it? Air? A goldfish? "Effect is much stronger on drinker" isn't particularly specific.

If this happens then the person who drank it gets significantly more vitamins than they would drinking vitamin water in a regular cup. Now about the effect, I wasn't really clear on this so I'll explain. If a the liquid in question has anything in it like sugar, there will be much more of it when the liquid is in the cup. If the liquid has caffeine in it, there will be a lot more in the liquid when in the cup, causing insomnia. I will explain this more in the original post.

2. Are you talking about light in the human visual spectrum? The butterfly's visible spectrum? The mantis shrimp's? How would anyone be able to tell it's the color of light that affects the glass? Also, ditto on the goldfish question.

Electromagnetic spectrum; basically all the colors. As for your second question, there is no specific color that affects a specific liquid, instead any color can affect any liquid with different outcomes.

The issue I see at the moment is that both of these ideas toy with 'Input X, Output Y': the first in a 'crank it to 11' fashion while the second is (at the moment) completely random for randomness's sake.

Try to develop the idea a bit further past that. To get you started: Why do they work this way? Is there a specific purpose this was meant for? Is there anything interesting about their creation?

When a liquid is poured into the cup, the effect on the drinker is much much stronger than what it should be.

What if the cup is full of water? Or some other substance that doesn't have an obvious 'effect' on someone?

I dunno, I might find this idea interesting if you focused more on the actual chemistry of what was going on (does it look for particular types of molecules and replicate them?) but as it is, it's a little vague.